In an insulated wire, a resin insulating coating is disposed on a surface of a conductive wire body such as a copper wire. In a case where the insulated wire is subjected to soldering, an insulating coating of a urethane resin is decomposed by solder heat, and thus, it is possible to perform soldering without peeling off the insulating coating. However, an insulating coating other than the urethane resin is not decomposed by the solder heat, and thus, it is necessary to remove the insulating coating in a soldered portion.
As a method of peeling off the insulating coating of the insulated wire, a method of melting or burning the insulating coating by irradiating the insulating coating with a laser beam to remove the insulating coating as described in Japanese Unexamined Patent Application, First Publication No. H7-7825 is known, and a method of cutting an outer circumference of the insulating coating by a rotating cutter to remove the insulating coating as described in Japanese Unexamined Patent Application, First Publication No. 2002-101516 is known. Further, a method of pressing the insulating coating by cutters disposed to interposing the insulated wire therebetween and of peeling off the insulating coating according to feeding of the insulated wire as described in Japanese Unexamined Patent Application, First Publication No. 2003-217961 is known.
However, the method of peeling off the insulating coating by using the laser beam has a problem of a high equipment cost. On the other hand, it is difficult to apply the method of cutting the insulating coating by rotating the cutter to a rectangular insulated wire. In addition, the method of eliminating the insulating coating by interposing the insulating coating between the cutters has a problem in which disconnection easily occurs in an insulated wire having a fine wire diameter, and it is difficult to apply the method to an ultra thin wire having a wire diameter of less than or equal to 100 μm.